The present invention relates generally to power tools employing batteries to power various tool functions, and more specifically to a battery for such a tool.
The present battery is intended for use with power tools generally; however a preferred type of tool is portable, such as a combustion-powered fastener driving tool, also commonly referred to as a combustion tool or combustion nailer. Tools of this kind are manufactured by Illinois Tool Works, Inc. of Glenview, Ill. and are described in commonly assigned patents U.S. Pat. Nos. 4,552,162; 4,483,473; 4,483,474; 4,403,722 and 6,176,412, all of which are incorporated by reference herein.
Generally, such combustion tools incorporate a housing enclosing a small internal combustion engine. The engine is powered by a canister of pressurized fuel gas, also called a fuel cell. A powerful, battery-powered electronic power distribution unit produces the spark for ignition, and a fan located in the combustion chamber provides both an efficient combustion within the chamber, and facilitates scavenging, including the exhaust of combustion by-products. The engine includes a reciprocating piston with an elongate, rigid driver blade disposed within a cylinder. Such tools include electronic control systems, spark generators, electric fan motors, and other electronic components, and are powered by batteries.
Conventional power tool batteries are preferably rechargeable and are configured for releasably locking into place when electronically connected to a corresponding power tool. This locking engagement facilitates operation of the tool when subject to environmental stress and significant operational shock impacts that potentially cause disconnection and/or power disruption. Thus, one design criteria of such batteries is the ability to maintain the electrical connection while withstanding environmental stress and operational shock impact forces to which such tools are exposed.
Power tool batteries, like most batteries, have a pair of electrical terminals that contact corresponding electrical terminals on a battery module fastened inside a battery chamber in the tool housing. The connection between the respective battery and tool terminals enables the stored electrical energy in the battery to be transferred to the tool. It is therefore important to maintain consistent, even contact pressure between the respective terminals by aligning the battery with the battery module as shown in FIG. 1. Manufacturing variations occur, however, often resulting in misalignment between the battery module and the battery as shown in FIG. 2. When the battery and the battery module are misaligned, one of the terminals does not have sufficient contact to maintain proper tool operation.